javascript promises tutorial

This article mainly introduces the local implementation tutorial of JavaScript + html5canvas. If you are interested in functions, refer to the html5 APIs that you have recently learned, I found that Sina Weibo's profile picture settings were implemented using canvas. In addition, I learned some time ago that the html5 File API uses the File API FileReader to upload files.

JavaScript: About the collection and efficiency in JavaScript, Javascript tutorial An array is an internal object provided by JavaScript. It is a standard set. We can add (push), delete (shift) elements, we can also traverse the elements in the for loop, so can we have other

Javascript: Javascript calls XML to create a linkage drop-down box. Javascript tutorial The traditional HTML page uses two methods:1) directly store the content in the drop-down box in html javascript, and call the javascript func

JavaScript: The JavaScript reflection mechanism of AJAX. What is the reflection mechanism in the Javascript tutorial? The reflection mechanism means that the program can obtain its own information at runtime. For example, an object can know its methods and attributes at runtime. Use (... In ...) Statement reflection

always at the end of the scope chain. 3. Nested object members can significantly affect performance and are used sparingly. 4. The deeper the property or method is in the prototype chain, the slower the access speed. 5. In general, you can promote JavaScript performance by storing array elements, object members, and cross-domain variables in local variables, because accessing local variables is faster6. Use with as little as possible, because he will

This article describes how to create a JavaScript framework, including DOM and debugging of various attributes! If you need them, can you refer to them and find them incredible? Want to know how Dojo is implemented? Curious about JQuery's skills? In this tutorial, we will explore the secrets behind the framework and try to build a simple version of your favorite framework. We use various

This article describes how to create a JavaScript framework, including DOM and debugging of various attributes! If you need them, can you refer to them and find them incredible? Want to know how Dojo is implemented? Curious about JQuery's skills? In this tutorial, we will explore the secrets behind the framework and try to build a simple version of your favorite framework. We use various

JAVAScript: Page self-adaptation through JAVAScript. Javascript tutorial Sometimes, we may need to make some data display blocks adaptive according to the page size like the new Yahoo Mail. The fact is not difficult, but if we simply use CSS control, we often cannot fully implement the results we need. At this time, we

Javascript: Example: Try to write friendly Javascript code, Javascript tutorial In the Search Engine's robot Search, the "text" such as type, text, and html have the highest degree of friendliness (except for text/xml at present ), the friendliness of text and javascript is

dismiss a reference to object B> b=Null;NullPerform garbage collection again> Global.Gc(); undefined//release B after the reference, heapused change back to around 4M //description weakmap the length of 5*1024*1024 The array was destroyed > process. Memoryusage{rss: 20639744842547239797928956 " In the above code, as long as the external reference disappears, Weakmap internal references are automatically purged by garbage collection. This shows that with its help, it is much easie

Basic Javascript tutorial-break and continue statements, basic tutorial-continue The break and continue statements provide stricter Process Control for code execution in the loop. The break statement can immediately exit the loop to prevent any code in the loop body from being executed again. The continue statement only exits the current loop and allows the next

Let's take a look at a simple JS basic Introductory Tutorial , the use of classes to create changes, such as Oh, JavaScript introductory tutorials, create, JS tutorials, Getting started, JavaScript instantiation

This article introduces how to set the amount style in javascript to retain two decimal places. The following is a good tutorial. The Code is as follows: // Convert the amount formatFunction parsePrice (s ){Var n = 2 // set the number of reserved decimal placesS = parseFloat (s + ""). replace (/[^ \ d \.-]/g, ""). toFixed (n) + "";Var l = s. split (".") [0]. split (""). reverse ();Var r = s. split (".

Javascript: summary of the javascript pop-up window, Javascript tutorial Author: Luo daijun, ldj_work # 126.com. reposted to ensure integrity.1. No prompt to refresh the webpageHave you found that when refreshing some webpages, a prompt window will pop up and click "OK" to refresh the page.Some pages do not prompt. If

Javascript: Example: using Javascript to create sound buttons, Javascript tutorial Introduction: In general, buttons on a webpage do not trigger sound events. If you want the button to respond to the sound of the mouse action, you can write a JavaScript script code. The scri

JavaScript: Common JavaScript detection scripts. Javascript tutorial * ------------------------------------------------------------------------------- File Name: check. js Note: JavaScript scripts are used to check the input data of the webpage submission form. Version: 1.0

Javascript: use JavaScript to detect browser-related features. Javascript tutorial I. Check the browser nameProblem:Different browsers have different standard support for javascript. Sometimes you want the script to run well on different browsers. In this case, you need to c

Javascript: javascript reads and writes XML in IE and FireFox to achieve AD rotation. Javascript tutorial I recently updated my website homepage advertisement, ASP. NET ad controls can easily achieve this, but the homepage is a static page. Lenovo's ad Control Principle decides to use

There are two ways to use Third, the general wording of the reference external JavaScript file is: (note that you should not add extra in the middle of tags JavaScript code. If it is included, it is ignored. ）Iv. in comparison with external references, external references are maintainable and cacheable, so it is recommended that external references be used.Five, the location of the label storage. OrFor per

JS Getting Started Tutorial: JavaScript Try ... Catch Error Capture Instance tutorial One of the try ... catch declarations allows you to test the error of a block of code. ExampleOne of the try ... catch declarationsHow to compose a try ... catch statement. The confirmation box for the try ... catch declarationAnother example is how to write a try ... cat